5 DH_generate_key, DH_compute_key - perform Diffie-Hellman key exchange
9 #include <openssl/dh.h>
11 int DH_generate_key(DH *dh);
13 int DH_compute_key(unsigned char *key, BIGNUM *pub_key, DH *dh);
17 DH_generate_key() performs the first step of a Diffie-Hellman key
18 exchange by generating private and public DH values. By calling
19 DH_compute_key(), these are combined with the other party's public
20 value to compute the shared key.
22 DH_generate_key() expects B<dh> to contain the shared parameters
23 B<dh-E<gt>p> and B<dh-E<gt>g>. It generates a random private DH value
24 unless B<dh-E<gt>priv_key> is already set, and computes the
25 corresponding public value B<dh-E<gt>pub_key>, which can then be
28 DH_compute_key() computes the shared secret from the private DH value
29 in B<dh> and the other party's public value in B<pub_key> and stores
30 it in B<key>. B<key> must point to B<DH_size(dh)> bytes of memory.
34 DH_generate_key() returns 1 on success, 0 otherwise.
36 DH_compute_key() returns the size of the shared secret on success, -1
39 The error codes can be obtained by L<ERR_get_error(3)>.
43 L<dh(3)>, L<ERR_get_error(3)>, L<rand(3)>, L<DH_size(3)>
47 Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
49 Licensed under the OpenSSL license (the "License"). You may not use
50 this file except in compliance with the License. You can obtain a copy
51 in the file LICENSE in the source distribution or at
52 L<https://www.openssl.org/source/license.html>.